In a conventional vehicle upper structure, as illustrated in FIG. 10, a center pillar 80 extending in an up-down direction has an upper end coupled to a roof side rail member 84 comprising a roof side rail outer panel 81 and a roof side rail inner panel 82 and having a roof side closed cross-section 83 extending in a vehicle front-rear direction, and a lower end coupled to a side sill 89 comprising a side sill outer panel 85, a side sill reinforcement 86 and a side sill inner panel 87 and having a side sill closed cross-section 88 extending in the vehicle front-rear direction.
In the conventional structure illustrated in FIG. 10, during a vehicle side impact event, a side impact load is input to the center pillar 80 from the direction indicated by the arrow in FIG. 10, and the center pillar 80 directly receiving the side impact load is inwardly bent or deformed as indicated by the two-dot chain line alpha in FIG. 10, to absorb the side impact load by means of the deformation.
In other words, the conventional structure is configured to absorb a side impact load by permitting an inward bending of the center pillar 80 to some extent. However, this is problematic because it cannot be denied that there is a certain amount of intrusion of the center pillar 80 in a vehicle-width inward direction.
In the conventional structure illustrated in FIG. 10, no large load is input to a roof reinforcement serving as a reinforcing member mutually connecting right and left roof side rail members in a vehicle width direction, because the structure is configured to absorb a side impact load by means of an inward bending of the center pillar 80.
A vehicle upper structure intended to suppress an inward bending of a center pillar so as to solve the above problem has already been invented (see FIG. 11).
FIG. 11 illustrates a conventional vehicle upper structure as viewed upwardly from a bottom of a vehicle (bottom view), wherein: the reference numeral 90 indicates a left (& right) roof side rail member having a closed cross-section structure and extending in a vehicle front-rear direction; 91 indicates a roof reinforcement serving as a reinforcement member connecting the right and left roof side rail members 90, 90 in a vehicle width direction; 92 indicates a left (& right) center pillar having a closed cross-section structure and extending in an up-down direction; and 93 indicates a left (& right) gusset coupling the roof reinforcement 91 and the left (& right) roof side rail member 90 together. The left (& right) gusset 93 is fastened to an inner panel of the left (& right) roof side rail member 90, i.e., a left (& right) roof side rail inner pane, by using a pair of front and rear fastening bolts 94, 94, and fastened to a lower surface of the roof reinforcement 91 by using a pair of front and rear fastening bolts 95, 95.
In relation to suppressing the inward bending of the center pillar 92, the conventional structure illustrated in FIG. 11 is configured to increase rigidity of the center pillar 92.
In this structure, a side impact load input into the center pillar 92 during a vehicle side impact event is applied to the roof reinforcement 91 via the gusset 93 located just above the center pillar 92 and fastening points of the bolts 95. However, if the load applied to the roof reinforcement 91 becomes fairly larger than that in the structure illustrated in FIG. 10, to cause an increase in bending moment imposed on the roof reinforcement 91, a problem will occur that the roof reinforcement 91 is bent in the middle thereof, and consequently the entire center pillar 92 falls inwardly.
As measures for preventing such middle bending of the roof reinforcement, it is conceivable to increase a wall thickness (i.e., plate thickness) of the roof reinforcement 91, and/or increase a width W of the roof reinforcement 91 in the vehicle front-rear direction, to increase rigidity of the roof reinforcement 91. However, this approach is disadvantage in terms of weight reduction.
When a side impact load is input from the center pillar 92, the load is also applied to an end 93a of the gusset 93 on a side fastened to the roof reinforcement. However, a width of the end 93a in the vehicle front-rear direction is kept equal to a width of the gusset 93 itself in the vehicle front-rear direction without modification, which is problematic in that the structure is not configured to sufficiently resist against a bending moment to be imposed on the roof reinforcement 91.
Meanwhile, the following Patent Literature (PTL 1) discloses a vehicle upper structure in which a lower surface of a roof reinforcement extending in a vehicle width direction is bolt-fastened to a roof side rail inner panel of a roof side rail member through an L-shaped gusset.
In the conventional structure disclosed in the PTL 1, an end of the gusset on a side fastened to the roof reinforcement is parallel to or approximately parallel to a line oriented in a vehicle front-rear direction. Thus, this structure is substantially equivalent to the conventional structure illustrated in FIG. 11, i.e., problematic in that it is not configured to sufficiently resist against a bending moment to be applied to the roof reinforcement.